There are various devices used to remove particles from air streams. Typically, in industrial applications, the devices are “cyclonic” devices that cause an air stream to rotate within a hollowed body so that particles move radially outward and engage the wall of the body so as to be removed.
Vacuum cleaners also use cyclonic devices and/or filters to remove particles and/or filaments. However, typically, domestic vacuum cleaners, and vacuum cleaners employed by professional cleaning staff, include at least one filter through which the air passes before it exits via the exhaust of the vacuum cleaner.
A disadvantage of “cyclonic” separators is that they do not remove all the material required. To address this issue, frequently filters are added at a position downstream of the “cyclonic” separator. However, this combination suffers from the disadvantage that the filters become blocked and the efficiency of the device diminishes.
The centrifugal systems also employ a filter located generally downstream of the main centrifugal part of the system. These filters also become blocked and therefore this is a disadvantage since flow rates through the system diminish.
The abovementioned “cyclonic” separators has a further disadvantage in that they operate efficiently only within relatively narrow ranges of operating conditions. For example, if air flow rates diminish, the separators become inefficient.